Protective paper and ink therefor



Patented Dec. 15, 1942 PROTECTIVE PAPER THEBEFOR Festas L. Minnen, Lombard, nl., mmm to Columbian Bank-Note Company, a corporation of Illinois 'Application July 15, 1940, Seria-l No. 345,641

(Cl. G-23) s claims.

This invention-relates to a protective paper and ink therefor, and more particularly to a paper adapted to undergo a permanently identiable reaction upon the application of ink eradicator or water thereto.

In the -manufacture of checks, negotiable instruments, and similar materials, there have been devised many ways of preventing alteration of the instruments. Some means involve the application to the paper of a special design which is aiected by any attempt at alteration. Other means include the printing of various layers of ink on the paper, often with one of the layers being printed in invisible ink, so that upon any attempt at alteration a predetermined design vill appear on the paper.

Similarly, there have been many types of to counterfeit. Various means for canceling these stamps to prevent reuse have also been provided. All of the means and methods devised, however, have had certain disadvantages, .and

of them have been so complicated and expensive as to be impracticable:

With my improved product, the difliculties and complexities heretofore encountered are obvlated.

Checks and similar instruments may be protected against alteration by merely printing on 4the surface thereof an ink, which, uponk later attempted alteration of the instrument, becomes readily identifiable. A single layer ofthe ink all that need be used in my protective paper. `When alterations are atempted and ink eradicator or other bleaching agent is used, the portion of the paper which is tampered with permanently Y changes color.

The product may also be made sensitive to water alone. This type of paper may be used Yas a revenue stamp, and canceled by merely dipping the same in water.

Other features and advantages of my invention will appear from the' following speciication and z :venue stamps prepared which are very difficult However, since some eradicators are reducing agents and tend to bleach the dye by reducing it,l the dye should also be capable of reduction, while the pigment should be diiilcult to reduce.

By a fugitive dye, I mean one which loses or changes itscolor upon 'the application of ink eradicator thereto.

The two coloring materials may be of different colors and may be blended together in the ink r.plied to the printed material, being capable of being loosened from the paper fibers when wet,

and thus being blotted or washed ou the printed sheet by immersion in water. On the other hand, v

the dye, although sensitive to ink eradicators. may be such that the bers in the paper are dyed to produce a print which is practically insensitive to water alone.

The pigment, which normally consists of chemically inactive. coloring material, is substantially insensitive to 'both water and ink eradlcators.

Iftheink contains a blend of a pigment and a fugitive dye, of which the print is substantially insensitive to water but sensitive to ink eradicators, any attempt to .alter the instrument by the applicaion of such eradicaor will cause the fugitive dye to lose its color. The color of the pigment will appear on the portion of the paper to drawing, which is a plan view of my protective paper, showing a portion of the paper upon which an alteration has been attempted.

The protective paper may include4 a paper base with a layer of ink printed thereon. The ink should contain a fugitive dye, whichv may be chemically reactive andl may be bleached by then the pigment should only be dlflicultly oxidizable.

. which the4 eradicator has been applied. In eifect,

a striking and permanent change in the color of the printing has been eifected.

If ,the fugitive dye in the print is sensitive to water as well as to ink eradicators. substantially the' same result will be. accomplished by treating the paper with water alone. l

The ink may be of any suitable composition adapted to serve as a carrier for the pigment and dye. It is preferably suitable for printing on a lithographie press in which a high etched zinc plate is used.f"It may, however, be used with letter press, intaglio plate, or other type of printing.

A TheV ink should contain suitable materials to provide body and printing properties. A mate- I l rial capable of swelling ory being dispersed in water, with or without the use of chemical cutting agents, should be included.v Examples of such materials are the natural and synthetic gums such as gum tragacanth, locust bean gum.

danger lof premature drying of ink. Among thehygroscopic materials which maybe used are glycerine, glucose, sorbitol, ethylene glycol, and

v diethylene glycol. l

vIfdesired, a preservative vsuch as phenol may be added to prevent bacterial growth.

The printing'material in the water together with the hygroscopic substances and the preservative comprise a water extended vehicle for the coloring materials. By water extended vehicle, I mean a water base or water soluble vehicle as distinguished from an oil base vehicle.

The coloring materials, which include a blend of one or more dyes with a pigment or pigments. are dissolved or dispersed in the vehicle. Dyes r may be selected from the well known groups of basic dyes, acid dyes, direct dyes, and spiritsoluble water-soluble dyes.

Among the dyes which have been' found to be satisfactory are the following acid dyes:

Patent Blue Fast Light Yellow Milling Yellow Milling Red Alizarine Fast Blue All of these dyes are sensitive to ink'eradicators.

and all of them, with the exception of Alizarine Fast Blue, are readily sensitive to water in the print. Alizarine Fast Blue is only slightly or partially sensitive-to water in the print.

'Ihe dry color .or pigment may include such substances as:

Lithol Rubine Red Milori Blue Hansa Yellow A specific example of an ink which is sensitive to both water and ink eradicators comprises approximately 86% of a vehicle of White Corn l Dextrine mixed with water, glycerine, and phenol in suitable proportions to obtain the proper consistency and coloring materials in the amount of approximately 14% by weight.

The 14% coloring materials may be madev of the following substances: A

- Per cent ,Patent Blue (dye) 2.9 Lithol Rubine Red (pigment) 9.6 Hansa Yellow (pigment) 1.4

The dextrine and water are cooked together in the usual manner. Glycerine and phenol are pigments are then added and ground on a roller 4inl: mill until the mixture is uniform.

Lithographie prints made from ink are4 bluish gray in color.V The prints are sensitive to both water and ink eradicators, and after treatment with either leave a permanent red blot on the portion of the paper which has been treated. Thus as seen in the drawing, a paper base I0, carrying a layer of the ink I|..of the surface thereof, has an exposed portion l2 which is red in color, showing where the eradicaton has been applied to the paper.

When a water sensitive fugitive dye is included in the ink, and the protective paper produced thereby is used as a revenue stamp, the stamp may be canceled by merely dipping the same in water. In this event, the water sensitive dye is dissolved by the water and bleeds out, leaving the i dry color or pigment. Accordingly. the color of to ink eradicators and a pigment, the prints may be identied as genuine by the application of an eradlcator or specic chemicals. Even more important is the fact that any attempted altera tions become apparent immediately uponl treatmen-t with the ink eradicator.

f The foregoing specific examples have been given for the purpose of illustrating the invention and means of practicing yit. Changes and modications may, therefore, be made in the product as set forth, particularly as to nature and quantities of the ingredients used, without departing from the spirit and scope of my invention as set forth in the appended claims, in which it is intended to claim all novelty inherent in the invention as broadly as permissible in view of theprior art.

I claim: v

l. An ink of the character described adapted to be applied toa paper base to form a protective paper providing a permanently identifiable reaction upon the application of ink eradicator thereto. comprising a water-soluble vehicle, afugitive dye of one 'chromatic color dissolved in said vehicle. and a pigment of another chromatic color dispersed in the vehicle but substantially insoluble therein, said dye and said pigment being solved in said vehicle, and a red pigment dispersed'in said vehicle but substantially insoluble therein, said dye and said pigment being blended together to provide an ink of a color diiferent from thatof each of the constituents thereof.

,then incorporated in the mixture. The dyes and 3. Ay protective paper adapted to undergo a permanently identifiable reaction upon the appllcation of an ink eradicator thereto, comprising apaper base, a water-soluble vehicle. on said base, g a -fugitive 'dye of one chromatic color dissolved 

